DE936488C - Cyclone dust collector - Google Patents

Description

(WiGBl. P. 175)

ISSUED DECEMBER 15, 1955

P33304 Hl 150eD

Cyclone dust collector

The invention relates to a cyclone dust separator for cutting off the finest dust particles of gases with a separation space and one behind it or, in the case of the preferred vertical one Type of construction arranged underneath the collecting container, in which between the individual rooms one each an annular gap shielded from the following space is provided and enters the separation space the immersion tube serving to discharge the purified gas opens.

It is known to extract small particles from gases, e.g. B. for the purpose of cleaning the air in workshops, the removal of fly ash from flue gases, for the pre-cleaning of blast furnace gases or for separation to be separated from the conveyed material in pneumatic conveying systems in cyclone separators and deposit. These cyclone separators, which are mostly designed as rotationally symmetrical containers the gases with the admixtures are fed in eccentrically at high speed, the specifically heavier additions to the outside under the influence of centrifugal force reach the wall of the container and the cleaned gases pass through a centric in the cyclone axis arranged immersion tube are discharged. Due to the friction that will be on the container wall the admixtures are inhibited in their movement and get in with the help of gravity a collecting container from where they can be removed at intervals.

These separators have proven themselves for separating dust in certain cases; but they fail to separate very fine dust and flours in the order of magnitude of about S μ and below,

also with very valuable materials, e.g. B; in pharmaceutical products and in the food industry, where value must be placed on practically complete dedusting. In these cases it is therefore often necessary to install filters or electrical filters behind or in place of the cyclone separator To arrange dedusting systems. However, the high acquisition and operating costs make such systems are often uneconomical. Attempts have therefore already been made to use smaller Cyclone separators and, through higher gas speeds, the centrifugal forces acting on the smallest parts and thus to increase the degree of separation. Even if in some cases this results in certain Improvements were made, so the success fell far short of expectations, and it did a practically complete dedusting could not be brought about in this way.

The difficulties mentioned are avoided in a dust separator according to the invention by that all parts are coaxial and rotationally symmetrical to the immersion tube. It succeeds on this way, even fine and finest dust and flour can be separated practically completely in the cyclone separator. A compressed dust gas mixture is created in the separation room and in the collecting container a certain negative pressure is generated, which fully loads the dust gas mixture with the separated dust inevitably sucked out of the separation chamber and this partial gas flow either for further cleaning can get into the separation room or completely cleaned into the immersion tube.

For this purpose, there is a rotationally symmetrical one between the separation space and the collecting container conical or cylindrical built-in part is provided, between the edge and the wall of the Container an annular gap remains free. This gap is used to compress the material in the separation space Extracted dust gas mixture, which favors the dust transport downwards, the dust density is reduced and any re-turbulence is avoided. It has been shown to be beneficial to choose the diameter of the gap equal to or larger than the immersion tube diameter. Furthermore, According to the invention, the separation chamber is designed so that its diameter is downwards continuously decreases, in such a way that the separation space in a longer, weak conical middle and a shorter, strongly conical lower section is divided ', while the upper cylindrical part is restricted to the area of the eccentric entry of the raw gas is. This ensures that at the critical points with a smaller center distance greater accelerations occur in the boundary layer and thus the boundary layer thickness is reduced will. This results in a substantial reduction in the turbulence in the boundary layer and consequently a significant reduction in dust transport across the direction of flow. With appropriate, The acceleration to be set on a case-by-case basis may, under certain circumstances, be laminar Flow in the boundary layer can be achieved, which every dust transport transversely to the flow direction completely excludes.

Together with these measures, in specially stored cases at the dip tube inlet or, without a passage gap, then a cylindrical one, narrower in diameter, of the same size or another permeable piece of pipe is arranged. This permeable piece of pipe can be as Sieve tube, wire, thread or mesh grids can be formed, which means that the separation efficiency is increased results in a substantial reduction in pressure losses. By means of the sieve tube can be through each determining the arrangement of the bores and openings along the sieve-like surface area uniform Inflows and thus achieve the same radial flow velocity everywhere. this means the same locking effect along the entire surface, completely or partially Occurring reduction in the swirl when flowing through the screen jacket and thus the reduction or avoidance of the rotation of the exhaust gas flow within the immersion tube.

The purpose of the collecting container is, on the one hand, to bring about the settling of the dust and on the other hand, to generate the required negative pressure for sucking off the dust gas mixture. this can be achieved by the fact that the diameter the dust collector is chosen to be relatively large. Furthermore, by special Measures, e.g. B. by shielding the dust separation room against the collecting container means a conical or cylindrical built-in part or by installing twist-reducing partition walls, the gas delivery through the dust collector can be increased.

To achieve an even and perfect dust separation and at the same time the dimensions To be able to keep the dust collector small, in special cases one of the Separation chamber extracted, compressed dust gas mixture in a second or further, under the first or further separation chamber arranged cyclone separator still further compressed and only aiii the end of the dust collection container, which can also be designed as a settling container, sucked off. The swirl that is still present in the first separation space is used in each subsequent separation space further reduced and also further reduced in the collecting container. To with one such double or multiple high-performance cyclone separator in the second and possibly in each additional separator has approximately the same blocking effect as in the first or previous one the following separator is used to compensate for the D rail loss executed with a correspondingly smaller diameter.

In the drawing, several exemplary embodiments of the device 'according to the invention' are shown in FIG Longitudinal sections illustrated schematically. It shows

Fig. Ι a dust collector with continuous Removal of dust,

Fig. 2 the separator with residual gas discharge through a rotationally symmetrical one in the cyclone axis Mounting part arranged opening,

Fig. 3 a modified form of the rotationally symmetrical built-in part in the cutout,

Fig. 4 shows the arrangement of a sieve tube that is connected to the immersion tube with a gap here, for example, is kept narrower in diameter than the immersion tube,

ίο Fig. 5 a double cyclone separator for extremely fine dust,

Fig. 6 the simplest version of a separator with a relatively large gap width between the separation room and the collecting tank,

Fig. 7 a partial section of a variant with a sieve tube divided at the bottom by a partition, at to which the gases flowing in from the opening of the built-in part take the detour around the partition wall are forced to do.

The separation space α of the cyclone separator is slightly conical in its part c adjoining the inlet b of the dust gas mixture and more conically narrowed in the following part d. This example of the structural shape results from manufacturing reasons as well as the gas routing proposed according to the invention in the separation space α and in the collecting container g. It can be changed to a large extent, but is appropriate for the intended flow division and its effects. The gap f is provided between part d and the rotationally symmetrical part e , through which the dust particles, together with the compressed gas residue, are inevitably sucked into the collecting container g . These residual gases leave the collecting container g either through the gap f, whereby the friction losses on the jacket of the insert cone e cause a flow division, namely a return flow directly up the cone wall and a flow running down the outer edge of the gap / down, or they are caused by the opening h sucked off. If the gas is to return through the widened gap f (Fig. 6), pressure differences can be caused by deformations at the gap, causing a suction at one point of the annular gap and a backflow at another point. It is advantageous to increase the circulation through the dust collecting container g by roughening the conical shell in a directed manner or by dividing the rotationally symmetrical built- in part e into sections with different conicity.

The immersion tube i serves to draw off the purified gases and can, according to the invention, in the given case be continued through the sieve tube k, which is narrower or wider in diameter. The sieve tube k is expediently led down to the jacket of the built-in part e or e ' and thus closed off at the bottom. The sieve tube k can also be closed off by a special cover plate, so that the gases drawn off must pass through the permeable sieve tube jacket in order to get into the interior of the sieve tube Ic and further through the immersion tube i into the open air or into the circuit. If an intermediate closing plate 0 (Fig. 7) is inserted into the sieve tube k above the gas outlet opening h , the gases are forced to flow around the plate 0 first outwards and then inwards again, whereby this gas residue is cleaned again and the dust transport in the collecting container g is favorably influenced.

In the sieve tube jacket k , round, oval or polygonal openings / are provided, which can be partially covered. The sieve tube jacket k can also consist of a wire, mesh or thread grid or the like, the mesh size of which is selected on a case-by-case basis. As a result of the installation of the sieve tube k , all or most of the purified gas is forced to flow through its openings /, and only a small part can optionally exit directly into the immersion tube i through the gap m.

By means of a suction pipe η (Fig. 1), the residual dust gas mixture that accumulates in the collecting container g is continuously drawn off into a dust chamber (not shown) and vented there. In the other case, the dust collecting container g is kept so large that the dust particles can settle under the action of gravity and, moreover, the suction effect necessary for suction is achieved. The swirl reduction in the collecting container g can, if necessary, be brought about by internals that are not shown. The suction effect is further increased by the rotationally symmetrical built-in part e projecting into the separation space α .

For special purposes, doubling the cyclone separator according to Fig. 5 or a multiple arrangement has proven to be beneficial. The functions of the parts labeled with the same letters are analogous; Corresponding parts are marked with a prime in the second cyclone separator. The two separators α and a and the dust collector g are arranged one above the other. The dust-air mixture withdrawn from the first separator a is further compressed in the second separator a ' and only then reaches the dust-collecting container g as a residual dust gas mixture. In order to achieve the same or similar blocking effect in the second separator a ' as in the first separator α , the loss of swirl is compensated for by reducing the diameter of the wall c' and d 'of the separating space a' .

Briefly summarized, the cyclone dust separator according to the invention differs from the previous cyclone vortexes in that from ■ the separation spaces α or a ' not dust alone, but a compressed residual dust gas mixture reaches the collecting container g. Due to the compulsory suction, in which the rotationally symmetrical built-in part e or e ' has an influential share due to its special shape, the downward transport of dust is accelerated, the dust density is reduced and losses or waste caused by re-whirling are avoided. At the critical points, the center distance is reduced

the container wall, ζ. B. by their conicities c and d or c ' and d', and by other measures the boundary layer is accelerated, the boundary layer thickness and its turbulence are reduced. As a result, there is practically no more dust transport transversely to the direction of flow. The dust gets down and through the residual gas extraction safely into the. Collection container g, where it is left to move from. To be withdrawn from time to time or continuously..Due to the correspondingly large dimensioning of the dust collection container g in connection with the reduction in the swirl, the complete separation of the dust of the dust gas mixture extracted from the separation space a is guaranteed.

Claims (8)

PATENT CLAIMS: 1. Cyclone dust separator for separating the finest dust particles from gases with a separation space and a collecting container behind it, preferably underneath, in which an annular gap is provided between the individual spaces that is shielded from the following space and in the separation space one for discharging the purified gas serving immersion tube opens, characterized in that all parts are coaxial and rotationally symmetrical to the immersion tube (i) . 2. cyclone dust separator according to claim i, characterized in that the annular gap (/) is formed by installing a conical body (e) in a circular opening of the same diameter as the immersion tube (i) , the conical body (e) the Covering the opening so far that the annular area of the gap (/) corresponds to about half to a quarter of the full circular cross-section of the opening. 3. Cyclone dust separator according to claims ι and 2, characterized in that parts of the inner wall and the built-in part (e) are roughened or provided with small disruptive bodies to increase the flushing between the separation space (α) and the dust collection container (g). 4. cyclone dust separator according to claims 2 and 3, characterized in that the walls of the separation space (α) are conical, the conicity before the transition in the dust collector increases more. 5. cyclone dust separator according to claims ι to 4, characterized in that a permeable or impermeable rotationally symmetrical counter-stand body (k) is installed in the cyclone axis, which is equal to or smaller than the immersion tube diameter in the largest diameter. 6. cyclone dust separator according to claim 5, characterized in that the resistance body (k) consists of a sieve-like cylindrical jacket, the diameter of which is equal to or smaller than the immersion tube diameter. 7. cyclone dust separator according to claims ι to 6, characterized in that the conical mounting part (e) has a central opening (h) which serves to discharge the clean gas obtained in the collecting container (g) to the immersion pipe (i). 8. Cyclone dust separator according to An-Proverbs 1 to 7, characterized in that the separation space is divided into several successive sub-spaces (a, a ') and the dimensions of the sub-spaces decrease in the direction of flow. Referred publications:
German Patent Nos. 227653, 247339, 529, 587 474, 598 423, 610 676, 657 867, 6617 ^ 4, 705339, 757 739; Swiss Patent No. 254 790; British Patent No. 297,543; U.S. Patent No. 1,835,445; Journal "Archives for Heat Industry and Steam Boilers", Vol. 25, Issue 5/6 May / June 1944, p. 95. 1 sheet of drawings 1 509 601 12.55